WO2018135114A1

WO2018135114A1 - Orientation control device, holding device, orientation control method, and program

Info

Publication number: WO2018135114A1
Application number: PCT/JP2017/040848
Authority: WO
Inventors: 象村越; 秀年椛澤; 智宏松本; 雅博瀬上; 功誠山下
Original assignee: ソニー株式会社
Priority date: 2017-01-19
Filing date: 2017-11-14
Publication date: 2018-07-26
Also published as: DE112017006862T5; CN110192150B; US10969662B2; CN110192150A; US20200041877A1

Abstract

[Problem] To provide a technology capable of accurately controlling the orientation of an item being held. [Solution] This orientation control device is equipped with a control unit. The control unit controls the orientation of an item to be held by controlling the orientation of a holding device for holding the item to be held on the basis of the direction of gravity, and determines the direction of gravity on the holding device on the basis of a static acceleration component calculated on the basis of a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on the holding device, and a second acceleration detection signal obtained by detecting the static acceleration component and the dynamic acceleration component acting on the holding device.

Description

Attitude control device, holding device, attitude control method, and program

This technology relates to a technology for controlling the posture of a holding device that holds a holding object.

Conventionally, a camera gimbal has been widely known as an apparatus for enabling a camera to stably capture an image (see, for example, Patent Document 1). The camera gimbal has a mechanism that rotates the camera about two axes or three axes, and controls the posture of the camera in space by rotating this mechanism.

The camera gimbal is generally used by being held by a hand or installed at a predetermined place, but in recent years, it may be used by installing it on a flying object such as a drone. (For example, refer to Patent Document 2).

JP 2002-369046 A JP 2016-219941 A

For example, in order to enable the camera to stably capture images, it is necessary to accurately control the posture of the camera. Therefore, it is important to accurately control the posture of a holding object such as a camera.

In view of the circumstances as described above, the purpose of the technology is to provide a technology capable of accurately controlling the posture of the object to be held.

In order to achieve the above object, the attitude control device according to the present technology includes a control unit. The control unit includes a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding target, and the dynamic acceleration component and static acceleration component acting on the holding device. Based on the static acceleration component calculated on the basis of the second acceleration detection signal obtained by detecting, and determining the direction of gravity in the holding device, and on the basis of the direction of gravity, The posture of the holding object is controlled by controlling the posture.

In this posture control device, the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding device, and the dynamic acceleration component and the static acceleration component acting on the holding device are obtained. The static acceleration component is calculated from the two signals including the second acceleration detection signal. For this reason, the static acceleration component that can be regarded as the gravitational acceleration component can be accurately calculated, and thereby the gravity direction of the holding device can be accurately determined. Accordingly, the posture of the holding device can be accurately controlled, and as a result, the posture of the holding object held by the holding device can be accurately controlled.

In the attitude control device, the control unit corrects the static acceleration component based on correction information for correcting the static acceleration component, and determines the gravity based on the corrected static acceleration component. The direction may be determined.

Thereby, the gravity direction of the holding device can be determined more accurately, and the posture of the holding object can be controlled more accurately.

In the attitude control device, the control unit may correct the static acceleration component based on the correction information for correcting the static acceleration component by the dynamic acceleration component.

In the attitude control device, the control unit may correct the static acceleration component based on the correction information for correcting the static acceleration component by an angular velocity component acting on the holding device.

In the attitude control device, the control unit may generate the correction information in a state where the holding device is placed at a certain place.

This makes it possible to obtain correction information by performing calibration while the holding device is stationary.

In the attitude control device, the holding device may be attached to a flying object, and the control unit may generate the correction information in a state where the flying object is in the air.

This makes it possible to obtain correction information by performing calibration while the flying object is in the air.

The attitude control device may further include an acceleration calculation unit. The acceleration calculation unit converts the first acceleration detection signal having an AC waveform corresponding to the dynamic acceleration component and an AC component corresponding to the dynamic acceleration component into a DC component corresponding to the static acceleration component. The static acceleration component is calculated on the basis of the second acceleration detection signal having the superimposed output waveform.

In the attitude control apparatus, the acceleration calculation unit includes an arithmetic circuit that calculates the static acceleration component based on a difference signal between the first acceleration detection signal and the second acceleration detection signal. May be.

Thereby, the static acceleration component can be accurately calculated from the first acceleration detection signal and the second acceleration detection signal.

In the attitude control device, the acceleration calculation unit further includes a gain adjustment circuit that adjusts the gain of each signal so that the first acceleration detection signal and the second acceleration detection signal have the same level. May be.

Thereby, the static acceleration component can be calculated more accurately from the first acceleration detection signal and the second acceleration detection signal.

In the attitude control device, the acceleration calculation unit calculates a correction coefficient based on the difference signal, and uses the correction coefficient to calculate one of the first acceleration detection signal and the second acceleration detection signal. You may further have the correction circuit which correct | amends.

In the attitude control device, a movable portion that can move by receiving an acceleration acting on the holding device, and a piezoelectric-type first acceleration detection portion that is provided in the movable portion and outputs the first acceleration detection signal; And a non-piezoelectric second acceleration detection unit that is provided in the movable unit and outputs the second acceleration detection signal.

In this attitude control device, the static acceleration component is accurately calculated from these outputs by using the difference between the detection methods (piezoelectric type and non-piezoelectric type) of the first acceleration detection unit and the second acceleration detection unit. can do.

In the attitude control device, the second acceleration detection unit may include a piezoresistive acceleration detection element. Alternatively, the second acceleration detection unit may include a capacitance type acceleration detection element.

The attitude control device according to another aspect of the present technology includes a control unit. The control unit includes a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding object held by the holding device, and the dynamic acceleration component and static acceleration acting on the holding object. Based on the static acceleration component calculated based on the second acceleration detection signal obtained by detecting the component, the gravity direction in the holding object is determined, and the holding device is determined based on the gravity direction. The posture of the holding object is controlled by controlling the posture.

In this attitude control device, the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding object, and the dynamic acceleration component and the static acceleration component acting on the holding object are obtained. The static acceleration component is calculated from the two signals including the second acceleration detection signal. For this reason, the static acceleration component that can be regarded as the gravitational acceleration component can be accurately calculated, and thereby the gravitational direction of the holding target can be accurately determined. Therefore, the posture of the holding device that holds the holding target can be accurately controlled, and as a result, the posture of the holding target can be accurately controlled.

The holding device according to the present technology includes a detection unit and a control unit. The detection unit includes a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding target, and the dynamic acceleration component and static acceleration component acting on the holding device. And a second acceleration detection signal obtained by detecting. The controller determines a gravitational direction in the holding device based on the static acceleration component calculated based on the first acceleration detection signal and the second acceleration detection signal, and based on the gravitational direction. Then, the posture of the holding object is controlled by controlling the posture of the holding device.

The attitude control method according to the present technology includes a first acceleration detection signal obtained by detecting a dynamic acceleration component that acts on a holding device that holds a holding target, the dynamic acceleration component that acts on the holding device, and Based on the static acceleration component calculated based on the second acceleration detection signal obtained by detecting the static acceleration component, the direction of gravity in the holding device is determined, and based on the direction of gravity, The posture of the holding object is controlled by controlling the posture of the holding device.

The program according to the present technology includes a first acceleration detection signal obtained by detecting a dynamic acceleration component that acts on a holding device that holds a holding target, the dynamic acceleration component that acts on the holding device, and a static Determining a gravitational direction in the holding device based on the static acceleration component calculated based on a second acceleration detection signal obtained by detecting an acceleration component, and based on the gravitational direction, Controlling the posture of the holding device by controlling the posture of the holding device.

As described above, according to the present technology, it is possible to provide a technology capable of accurately controlling the posture of the holding target.

1 is a perspective view showing a camera gimbal according to a first embodiment of the present technology. It is a block diagram which shows the structure of a camera gimbal. It is a block diagram which shows the structure of a sensor unit. It is a perspective view of the surface side which shows the structure of an acceleration sensor roughly. It is a perspective view of the back side which shows the composition of an acceleration sensor roughly. It is a top view of the surface side which shows the structure of an acceleration sensor roughly. It is a figure which shows a mode when the acceleration is not applied in an acceleration sensor. In an acceleration sensor, it is a figure which shows a mode when the acceleration has generate | occur | produced along the X'-axis direction. In an acceleration sensor, it is a figure which shows a mode when the acceleration has generate | occur | produced along the Z'-axis direction. It is a circuit diagram which shows one structural example of an acceleration calculating part. It is a figure which shows the processing block which calculates a static acceleration component from the acceleration detection signal of a X 'axis direction. It is a figure explaining one effect | action of the said acceleration calculating part. It is a figure explaining one effect | action of the said acceleration calculating part. It is a figure explaining one effect | action of the said acceleration calculating part. It is a figure explaining one effect | action of the said acceleration calculating part. It is a figure explaining one effect | action of the said acceleration calculating part. It is a figure explaining one effect | action of the said acceleration calculating part. It is a flowchart which shows the process of the control part of the camera gimbal which concerns on 1st Embodiment. It is a flowchart which shows the process of the control part of the camera gimbal which concerns on 2nd Embodiment. It is a flowchart which shows the process of the control part of the camera gimbal which concerns on 3rd Embodiment.

Hereinafter, embodiments of the present technology will be described with reference to the drawings.

<< First Embodiment >>
<Overall Configuration of Camera Gimbal 50 and Configuration of Each Part>
[External configuration of camera gimbal 50]
FIG. 1 is a perspective view showing a camera gimbal 50 according to the first embodiment of the present technology.

As shown in FIG. 1, the camera gimbal 50 (holding device: attitude control device) is attached in order from the top to the grip portion 51, the shaft portion 52, and the shaft portion 52 so as to be rotatable. And a rotating member 53. The camera gimbal 50 includes a second rotating member 54 that is rotatably attached to the first rotating member 53, a pedestal holding member 55 that is fixed to the second rotating member 54, and a pedestal holding member 55. And a pedestal 56 attached rotatably.

In the description in this specification, a coordinate system based on the earth is called a global coordinate system, and a coordinate system based on the pedestal 56 (camera) is called a local coordinate system. In the global coordinate system, the three orthogonal axes are the X axis, the Y axis, and the Z axis, and the three orthogonal axes in the local coordinate system are the X ′ axis, the Y ′ axis, and the Z ′ axis.

The Z-axis direction in the global coordinate system is the gravity direction, and the X-axis and Y-axis directions are arbitrary directions in the horizontal direction. Further, the Z′-axis direction in the local coordinate system is the thickness direction in the pedestal 56, the X′-axis direction is the longitudinal direction in the pedestal 56, and the Y′-axis direction is the short direction in the pedestal 56.

In the description of the present specification, the direction of the rotation axis when the first rotation member 53 rotates with respect to the shaft portion 52 is the z-axis direction, and the second rotation member 54 is the first rotation member 53. The direction of the rotation axis when rotating with respect to the y-axis is defined as the y-axis direction. The direction of the rotation axis when the pedestal 56 rotates relative to the pedestal holding member 55 is defined as the x-axis direction.

Here, in the example shown in FIG. 1, the X′-axis direction in the local coordinate system is the same as the x-axis direction that is the rotation axis direction. Also, the Y′-axis direction in the local coordinate system is the same as the y-axis direction that is the rotation axis direction. On the other hand, the Z′-axis direction in the local coordinate system may be different from the z-axis direction that is the rotation axis direction (for example, when the pedestal 56 rotates around the x-axis and y-axis from the state shown in FIG. 1). . The camera gimbal 50 may be configured such that the pedestal 56 can be rotated in accordance with the Z ′ axis direction in the local coordinate system.

Hereinafter, the posture of the camera gimbal 50 when the Z-axis direction in the global coordinate system and the Z′-axis direction (and z-axis direction) in the local coordinate system coincide with each other is referred to as a basic posture.

The grip portion 51 and the shaft portion 52 are integrally formed, and are formed so that one cylindrical member is bent at a right angle at the center. The grip part 51 is a member that is gripped by the user, and is configured to extend in a direction orthogonal to the z-axis direction.

The shaft portion 52 is configured to extend in the z-axis direction, and holds the first rotating member 53 at its lower end portion so as to be rotatable around the z-axis.

The first rotating member 53 is a plate-like member formed such that the center is bent at a right angle, and the upper half is configured to extend in the y-axis direction, and the lower half is the z-axis. It is comprised so that it may extend in a direction. The first rotating member 53 is held at the upper end portion so as to be rotatable around the z axis with respect to the shaft portion 52, and the second rotating member 54 is held at the lower end portion so as to be rotatable around the y axis. Yes.

The second rotating member 54 is a columnar member extending in the y-axis direction. The second rotating member 54 is held at one end so as to be rotatable around the y axis at the lower end of the first rotating body, and holds the pedestal holding member 55 fixed at the other end. .

The base holding member 55 is composed of two members formed symmetrically with respect to the zy plane. The pedestal holding member 55 is a cylindrical member, and is formed such that two places are bent at a right angle. The pedestal holding member 55 is fixed to the second rotating member 54 at one end thereof, and holds the pedestal 56 at the other end so as to be rotatable around the x axis.

The pedestal 56 is a rectangular plate-like member, and is held by a pedestal holding member 55 so as to be rotatable around the x axis. A camera (holding object) (not shown) is fixed to the upper surface of the base 56. Inside the pedestal 56, a sensor unit 40 that detects acceleration and angular velocity in three axis directions (X ′ axis, Y ′ axis, Z ′ axis) of the pedestal 56 is disposed at the position of the center of gravity of the pedestal 56.

In the present embodiment, the first rotating member 53 rotates about the z axis, the second rotating member 54 rotates about the y axis, and the pedestal 56 rotates about the x axis. It is possible to rotate about 3 axes (x axis, y axis, z axis) with respect to 51. In addition, although this embodiment demonstrates the case where the base 56 can rotate around 3 axes | shafts, the form which can be rotated about 1 axis | shaft or 2 axes | shafts may be sufficient.

In this embodiment, a mode in which the camera is fixed on the pedestal 56 will be described, but how the camera is fixed to the camera gimbal 50 is not particularly limited. For example, the camera may be fixed by being sandwiched from both sides in the x-axis direction with respect to the camera gimbal 50. In this case, the pedestal 56 can be omitted, and the sensor unit 40 is disposed in a portion (for example, a member sandwiched from the x-axis direction) that holds the camera that is the holding target.

Basically, the camera gimbal 50 is configured to be able to rotate the camera to be held around three axes (which may be one axis, two axes, etc.) and has the same movement as the camera. Any configuration may be used as long as the sensor unit 40 is arranged with respect to the portion to be operated.

[Function block configuration]
FIG. 2 is a block diagram showing the configuration of the camera gimbal 50. As shown in FIG. As shown in FIG. 2, the camera gimbal 50 includes a control unit 61, a sensor unit 40, a storage unit 62, a first motor 63a, a second motor 63b, and a third motor 63c. Yes.

The sensor unit 40 includes an acceleration sensor 10, an angular velocity sensor 30, and a controller 20. The acceleration sensor 10 detects the acceleration in the three-axis (X ′ axis, Y ′ axis, Z ′ axis) direction received by the pedestal 56 (camera) in the local coordinate system.

The angular velocity sensor 30 is, for example, a gyro sensor (vibration type, rotary top type, etc.), and detects the angular velocity around the three axes (X′Y′Z ′ axis) of the base 56 (camera) in the local coordinate system.

The controller 20 processes the output from the acceleration sensor 10 and the angular velocity sensor 30. In the present embodiment, for the acceleration received by the pedestal 56 (camera), the controller 20 includes a static acceleration component based on gravity (gravity acceleration component) and a dynamic acceleration component based on the motion of the pedestal 56 (camera) (motion acceleration component). ) Can be accurately separated and output to the control unit 61. The configuration of the sensor unit 40 will be described in detail later.

The control unit 61 includes a CPU (Central Processing Unit) or the like. The control unit 61 performs various calculations based on various programs stored in the storage unit 62 and controls each unit of the camera gimbal 50 in an integrated manner.

In particular, in the present embodiment, the control unit 61 determines the posture of the pedestal 56 and controls the posture of the pedestal 56, that is, the posture of the camera. Although details will be described later, in the present embodiment, the static acceleration component, that is, the gravitational acceleration component of the acceleration detection signal detected by the acceleration sensor 10 can be accurately calculated by the sensor unit 40. For this reason, in this embodiment, the control part 61 can determine the gravity direction of the base 56 correctly, and can control the attitude | position of the base 56, ie, the attitude | position of a camera correctly. The processing of the control unit 61 will be described in detail later.

The storage unit 62 includes various programs necessary for the processing of the control unit 61 and a non-volatile memory in which various types of data are stored, and a volatile memory used as a work area of the control unit 61.

The first motor 63a rotates the first rotating member 53 around the z-axis in response to a command from the control unit 61, and the second motor 63b receives the second motor 63b in response to a command from the control unit 61. The rotating member 54 is rotated around the y axis. The third motor 63c rotates the pedestal 56 around the x axis in response to a command from the control unit 61.

[Configuration of Sensor Unit 40]
Next, the configuration of the sensor unit 40 according to the present embodiment will be described in detail. FIG. 3 is a block diagram showing a configuration of the sensor unit 40.

The sensor unit 40 in the present embodiment is configured to be able to calculate a dynamic acceleration component and a static acceleration component from the acceleration detected by the acceleration sensor 10, respectively.

Here, the dynamic acceleration component typically means an AC component of an acceleration signal detected by the acceleration sensor 10, and typically, a motion acceleration (translation acceleration, centrifugal force) received by the base 56 (camera). Acceleration, tangential acceleration, etc.). On the other hand, the static acceleration component means a DC component of an acceleration signal detected by the acceleration sensor 10, and typically corresponds to gravitational acceleration or acceleration estimated as gravitational acceleration.

As illustrated in FIG. 3, the acceleration sensor 10 includes two types of acceleration detection units 11 and 12 (detection unit: first acceleration detection unit 11) that respectively detect information related to acceleration in three axis directions (local coordinate system). And a second acceleration detector 12). The angular velocity sensor 30 has an angular velocity detector 31.

The first acceleration detection unit 11 is a piezoelectric acceleration sensor 10 and includes a signal (Acc-AC-x) including information related to acceleration in the X′-axis direction and information related to acceleration in the Y′-axis direction. A signal (Acc-AC-y) including information related to acceleration in the Z′-axis direction is output. The signal output from the first acceleration detector 11 has an AC waveform corresponding to the acceleration of each axis.

On the other hand, the second acceleration detection unit 12 is a non-piezoelectric acceleration sensor 10 and includes a signal (Acc-DC-x) including information related to acceleration in the X′-axis direction, and acceleration related to the Y′-axis direction. A signal including information (Acc-DC-y) and a signal including information related to acceleration in the Z′-axis direction (Acc-DC-z) are output. The signal output from the second acceleration detector 12 has an output waveform in which an AC component corresponding to the acceleration of each axis is superimposed on the DC component.

The angular velocity detector 31 outputs an angular velocity detection signal (Gyro-x) around the X ′ axis, an angular velocity detection signal (Gyro-y) around the Y ′ axis, and an angular velocity detection signal (Gyro-z) around the Z ′ axis. To do.

The controller 20 includes a converter 204, a calculation unit 230, a serial interface 201, a parallel interface 202, and an analog interface 203.

The converter 204 performs AD (Analog-Digital) conversion on the signals detected by the acceleration sensor 10 and the angular velocity sensor 30 and outputs the signals to the calculation unit 230.

The calculation unit 230 includes an acceleration calculation unit 200 and an angular velocity calculation unit 300. The acceleration calculation unit 200 includes signals (Acc-AC-x, Acc-AC-y, Acc-AC-z) output from the first acceleration detection unit 11 and signals output from the second acceleration detection unit 12. (Acc-DC-x, Acc-DC-y, Acc-DC-z) based on the three-axis dynamic acceleration component (Acc-x, Acc-y, Acc-z) and static in the local coordinate system The respective acceleration components (Gr-x, Gr-y, Gr-z) are calculated.

Based on the signals (Gyro-x, Gyro-y, Gyro-z) output from the angular velocity detection unit 31, the angular velocity calculation unit 300 uses the angular velocities (ω-x, ω-y, ω-z) is calculated respectively.

The serial interface 201 is configured to sequentially output the dynamic acceleration component and static acceleration component calculated by the acceleration calculation unit 200 and the angular velocity component calculated by the angular velocity calculation unit 300 to the control unit 61. . The parallel interface 202 is configured to be able to output the dynamic acceleration component and the static acceleration component calculated by the acceleration calculation unit 200 and the angular velocity component calculated by the angular velocity calculation unit 300 to the control unit 61 in parallel. .

The controller 20 may include at least one of the serial interface 201 and the parallel interface 202, or may selectively switch the interface according to a command from the control unit 61. The analog interface 203 is configured to be able to output the outputs of the first acceleration detection unit 11, the second acceleration detection unit 12, and the angular velocity detection unit 31 as they are to the control unit 61, but may be omitted as necessary. .

[Configuration of Acceleration Sensor 10]
Next, details of the configuration of the acceleration sensor 10 will be described.

4 to 6 are a front perspective view, a rear perspective view, and a front plan view schematically showing the configuration of the acceleration sensor 10, respectively.

The acceleration sensor 10 includes an element body 110, a first acceleration detection unit 11 (first detection elements 11x1, 11x2, 11y1, 11y2), and a second acceleration detection unit 12 (second detection elements 12x1, 12x2, 12y1, 12y2).

The element main body 110 has a main surface portion 111 parallel to the X′Y ′ plane and a support portion 114 on the opposite side. The element body 110 is typically composed of an SOI (Silicon On On Insulator) substrate, an active layer (silicon substrate) that forms the main surface portion 111, and a frame-shaped support layer (silicon substrate) that forms the support portion 114. It has the laminated structure. The main surface portion 111 and the support portion 114 have different thicknesses, and the support portion 114 is formed thicker than the main surface portion 111.

The element body 110 has a movable plate 120 that can move under acceleration. The movable plate 120 is provided at the center of the main surface portion 111 and is formed by processing the active layer forming the main surface portion 111 into a predetermined shape. More specifically, the movable plate 120 having a plurality of (four in this example) blade portions 121 to 124 having a symmetrical shape with respect to the central portion of the main surface portion 111 is constituted by the plurality of groove portions 112 formed in the main surface portion 111. Is done. The peripheral portion of the main surface portion 111 constitutes a base portion 115 that faces the support portion 114 in the Z′-axis direction.

As shown in FIG. 5, the support portion 114 is formed in a frame shape having a rectangular recess 113 that opens the back surface of the movable plate 120. The support part 114 is configured as a bonding surface bonded to a support substrate (not shown). The support substrate may be a circuit board that electrically connects the acceleration sensor 10 and the controller 20, or may be a relay board or a package board that is electrically connected to the circuit board. Alternatively, the support portion 114 may be provided with a plurality of external connection terminals that are electrically connected to the circuit board, the relay board, and the like.

The blade portions 121 to 124 of the movable plate 120 are each constituted by a plate piece having a predetermined shape (in this example, a substantially hexagonal shape), and are arranged at 90 ° intervals around a central axis parallel to the Z ′ axis. The thickness of each of the blade portions 121 to 124 corresponds to the thickness of the active layer constituting the main surface portion 111. The blade portions 121 to 124 are integrally connected to each other at the central portion 120C of the movable plate 120, and are integrally supported so as to be movable relative to the base portion 115.

The movable plate 120 further includes a weight portion 125 as shown in FIG. The weight portion 125 is integrally provided on the back surface of the central portion of the movable plate 120 and the back surfaces of the blade portions 121 to 124. The size, thickness, and the like of the weight portion 125 are not particularly limited, and are set to appropriate sizes that can obtain the desired vibration characteristics of the movable plate 120. The weight portion 125 is formed, for example, by processing the support layer forming the support portion 114 into a predetermined shape.

4 and 6, the movable plate 120 is connected to the base portion 115 via a plurality (four in this example) of bridge portions 131 to 134. The plurality of bridge portions 131 to 134 are provided between the blade portions 121 to 124, respectively, and are formed by processing the active layer forming the main surface portion 111 into a predetermined shape. The bridge part 131 and the bridge part 133 are arranged to face each other in the X′-axis direction, and the bridge part 132 and the bridge part 134 are arranged to face each other in the Y′-axis direction.

The bridge portions 131 to 134 constitute a part of the movable portion that can move relative to the base portion 115, and elastically support the central portion 120C of the movable plate 120. Each of the bridge portions 131 to 134 has the same configuration, and as shown in FIG. 6, has a first beam portion 130a, a second beam portion 130b, and a third beam portion 130c.

The first beam portion 130a extends linearly from the peripheral portion of the central portion 120C of the movable plate 120 in the X′-axis direction or the Y′-axis direction, and is disposed between the blade portions 121 to 124 adjacent to each other. The The second beam part 130b extends linearly in the X′-axis direction or the Y′-axis direction, respectively, and connects the first beam part 130a and the base part 115, respectively.

The third beam portion 130c extends linearly in the directions intersecting with the X′-axis direction and the Y′-axis direction, respectively, an intermediate portion between the first beam portion 130a and the second beam portion 130b, and a base portion 115 are connected to each other. Each of the bridge portions 131 to 134 has two third beam portions 130c, and the two third beam portions 130c sandwich one second beam portion 130b in the X′Y ′ plane. Configured.

The rigidity of the bridge portions 131 to 134 is set to an appropriate value that can stably support the moving movable plate 120. In particular, the bridge portions 131 to 134 are set to have appropriate rigidity capable of being deformed by the weight of the movable plate 120, and the magnitude of the deformation is detected by the second acceleration detecting unit 12 due to gravity acceleration due to the own weight. If possible, it is not particularly limited.

As described above, the movable plate 120 is supported on the base portion 115 of the element main body 110 via the four bridge portions 131 to 134, and the base is provided with the bridge portions 131 to 134 as fulcrums by the inertial force according to the acceleration. It is configured to be movable (movable) relative to the portion 115.

7A to 7C are schematic side cross-sectional views for explaining the movement of the movable plate 120. FIG. FIG. 7A is a diagram illustrating a state when no acceleration is applied, and FIG. 7B is a diagram illustrating a state when acceleration is generated along the X′-axis direction. FIG. 7C is a diagram illustrating a state in which acceleration is generated along the Z′-axis direction.

In FIG. 7B, the solid line shows a state when acceleration occurs in the left direction of the paper, and the broken line shows a state when acceleration occurs in the right direction of the paper. In FIG. 7C, a solid line indicates a state when acceleration occurs in the upward direction on the paper surface, and a broken line indicates a state when acceleration occurs in the downward direction on the paper surface.

When the acceleration is not generated, the movable plate 120 is maintained in a state parallel to the surface of the base portion 115 as shown in FIG. 7A. In this state, for example, when acceleration along the X′-axis direction is generated, the movable plate 120 is inclined counterclockwise around the

bridge portions

132 and 134 extending in the Y′-axis direction as shown in FIG. 7B. As a result, the

bridge portions

131 and 133 facing each other in the X′-axis direction receive bending stresses in opposite directions along the Z′-axis direction.

Similarly, when acceleration along the Y′-axis direction occurs, the movable plate 120 tilts counterclockwise (or clockwise) about the

bridge portions

131 and 133 extending in the X′-axis direction, although not shown. The

bridge portions

132 and 134 facing each other in the Y′-axis direction receive bending stresses in opposite directions along the Z′-axis direction.

On the other hand, when acceleration along the Z′-axis direction occurs, the movable plate 120 moves up and down with respect to the base portion 115 as shown in FIG. 7C, and each of the bridge portions 131 to 134 moves along the Z′-axis direction. Subjected to bending stress in the same direction.

The first acceleration detection unit 11 and the second acceleration detection unit 12 are provided in the bridge portions 131 to 134, respectively. The acceleration sensor 10 detects the deformation caused by the bending stress of the bridge portions 131 to 134 by the first acceleration detection unit 11 and the second acceleration detection unit 12, so that the direction and magnitude of the acceleration acting on the acceleration sensor 10 are detected. Measure the thickness.

“Configuration of

Acceleration Detection Units

11 and 12”
Hereinafter, the first acceleration detection unit 11 and the second acceleration detection unit 12 will be described in detail.

As shown in FIG. 6, the first acceleration detection unit 11 includes a plurality (four in this example) of first detection elements 11x1, 11x2, 11y1, and 11y2.

The detection elements 11x1 and 11x2 are provided on the axial centers of the surfaces of the two

bridge portions

131 and 133 that face each other in the X′-axis direction, and one detection element 11x1 is provided on the first beam portion 130a in the bridge portion 131. The other detection element 11x2 is disposed on the first beam portion 130a of the bridge portion 133, respectively. On the other hand, the detection elements 11y1 and 11y2 are provided on the axial centers of the surfaces of the two

bridge portions

132 and 134 facing each other in the Y′-axis direction, and one detection element 11y1 is the first in the bridge portion 132. The other detection element 11y2 is disposed on the first beam portion 130a of the bridge portion 134, respectively.

The first detection elements 11x1 to 11y2 have the same configuration. In the present embodiment, the first detection elements 11x1 to 11y2 are formed of rectangular piezoelectric detection elements having long sides in the axial direction of the first beam portion 130a. . The first detection elements 11x1 to 11y2 are each composed of a laminate of a lower electrode layer, a piezoelectric film, and an upper electrode layer.

The piezoelectric film is typically made of lead zirconate titanate (PZT), but is not limited to this. The piezoelectric film generates a potential difference between the upper electrode layer and the lower electrode layer according to the bending deformation amount (stress) in the Z′-axis direction of the first beam portion 130a (piezoelectric effect). The upper electrode layers are electrically connected to the relay terminals 140 provided on the surface of the base portion 115 via wiring layers (not shown) formed on the bridge portions 131 to 134, respectively. The relay terminal 140 may be configured as an external connection terminal electrically connected to the support substrate. For example, the other end of a bonding wire whose one end is connected to the support substrate is connected. The lower electrode layer is typically connected to a reference potential such as a ground potential.

The first acceleration detection unit 11 configured as described above outputs only when there is a stress change due to the characteristics of the piezoelectric film, and does not output when the stress value is not changed even if stress is applied. Therefore, the magnitude of the motion acceleration acting on the movable plate 120 is mainly detected. Therefore, the output of the first acceleration detector 11 mainly includes an output signal having an AC waveform that is an AC component corresponding to the motion acceleration.

On the other hand, as shown in FIG. 6, the second acceleration detection unit 12 includes a plurality (four in this example) of second detection elements 12x1, 12x2, 12y1, and 12y2.

The detection elements 12x1 and 12x2 are provided on the axial centers of the surfaces of the two

bridge portions

131 and 133 facing each other in the X′-axis direction, and one detection element 12x1 is provided on the second beam portion 130b in the bridge portion 131. The other detection element 12x2 is disposed on the second beam portion 130b of the bridge portion 133, respectively. On the other hand, the detection elements 12y1 and 12y2 are provided on the axial centers of the surfaces of the two

bridge portions

132 and 134 facing each other in the Y′-axis direction, and one detection element 12y1 is the second in the bridge portion 132. The other detection element 12y2 is disposed on the second beam portion 130b of the bridge portion 134, respectively.

The second detection elements 12x1 to 12y2 have the same configuration. In this embodiment, the second detection elements 12x1 to 12y2 are configured by piezoresistive detection elements having long sides in the axial direction of the second beam portion 130b. The second detection elements 12x1 to 12y2 each include a resistance layer and a pair of terminal portions connected to both ends in the axial direction.

The resistance layer is, for example, a conductor layer formed by doping an impurity element on the surface (silicon layer) of the second beam portion 130b, and the amount of bending deformation of the second beam portion 130b in the Z′-axis direction. A resistance change corresponding to (stress) is caused between the pair of terminal portions (piezoresistance effect). The pair of terminal portions are electrically connected to the relay terminals 140 provided on the surface of the base portion 115 via wiring layers (not shown) formed on the bridge portions 131 to 134, respectively.

The second acceleration detector 12 configured as described above determines not only the motion acceleration acting on the movable plate 120 but also the movable plate 120 because the resistance value is determined by an absolute stress value due to the characteristics of the piezoresistance. It also detects the acting gravitational acceleration. Therefore, the output of the second acceleration detector 1211 has an output waveform in which a dynamic component (AC component) corresponding to the motion acceleration is superimposed on a gravitational acceleration or a static component (DC component) corresponding thereto.

Note that the second detection elements 12x1 to 12y2 are not limited to the example configured with the piezoresistive type detection elements, and other non-piezoelectric detection elements that can detect the acceleration of the DC component, such as an electrostatic type. It may be constituted by. In the case of the electrostatic type, the movable electrode portion and the fixed electrode portion constituting the electrode pair are arranged to face each other in the axial direction of the second beam portion 130b, and according to the amount of bending deformation of the second beam portion 130b. It is comprised so that the opposing distance between both electrode parts may change.

In the present embodiment, a piezoelectric acceleration sensor 10 is employed for the first acceleration detector 11, and a non-piezoelectric (piezoresistive or electrostatic capacitance) acceleration sensor 10 is employed as the second acceleration detector 12. Therefore, an inertial sensor having a wide dynamic range and high sensitivity in a low frequency region can be obtained.

The first acceleration detector 11 detects acceleration detection signals (Acc-AC-x, Acc) in the X′-axis direction, the Y′-axis direction, and the Z′-axis direction based on the outputs of the first detection elements 11x1 to 11y2. -AC-y, Acc-AC-z) are output to the controller 20 (see FIG. 3).

The acceleration detection signal (Acc-AC-x) in the X′-axis direction corresponds to a difference signal (ax1−ax2) between the output (ax1) of the detection element 11x1 and the output (ax2) of the detection element 11x2. The acceleration detection signal (Acc-AC-y) in the Y′-axis direction corresponds to a difference signal (ay1−ay2) between the output (ay1) of the detection element 11y1 and the output (ay2) of the detection element 11y2. The acceleration detection signal (Acc-AC-z) in the Z′-axis direction corresponds to the total sum (ax1 + ax2 + ay1 + ay2) of the detection elements 11x1 to 11y2.

Similarly, the second acceleration detector 12 detects acceleration detection signals (Acc-DC−) in the X′-axis direction, the Y′-axis direction, and the Z′-axis direction based on the outputs of the second detection elements 12x1 to 12y2. x, Acc-DC-y, Acc-DC-z) are output to the controller 20 (see FIG. 3).

The acceleration detection signal (Acc-DC-x) in the X′-axis direction corresponds to a difference signal (bx1−bx2) between the output (bx1) of the detection element 12x1 and the output (bx2) of the detection element 12x2. The acceleration detection signal (Acc-DC-y) in the Y′-axis direction corresponds to a difference signal (by1−by2) between the output (by1) of the detection element 12y1 and the output (by2) of the detection element 12y2. The acceleration detection signal (Acc-DC-z) in the Z′-axis direction corresponds to the sum (bx1 + bx2 + by1 + by2) of the outputs of the detection elements 12x1 to 12y2.

“Configuration of Acceleration Calculation Unit 200”
Next, the configuration of the acceleration calculation unit 200 of the controller 20 in the sensor unit 40 will be described. FIG. 8 is a circuit diagram illustrating a configuration example of the acceleration calculation unit 200.

The acceleration calculation unit 200 includes a gain adjustment circuit 21, a sign inversion circuit 22, an addition circuit 23, and a correction circuit 24. These circuits 21 to 24 have a common configuration for each of the X ′ axis, the Y ′ axis, and the Z ′ axis, and the dynamic acceleration of each axis is performed by performing common arithmetic processing on each axis. A component (motion acceleration component) and a static acceleration component (gravity acceleration component) are calculated.

Hereinafter, a processing circuit for an acceleration detection signal in the X′-axis direction will be described as an example. FIG. 9 shows a processing block for calculating a static acceleration component from the acceleration detection signal in the X′-axis direction.

The gain adjustment circuit 21 includes a first acceleration detection signal (Acc-AC-x) regarding the X′-axis direction output from the first acceleration detection unit 11 (11x1, 11x2), and a second acceleration detection unit 12 ( The gain of each signal is adjusted so that the second acceleration detection signals (Acc-DC-x) in the X′-axis direction output from 12 × 1, 12 × 2) have the same level. The gain adjustment circuit 21 includes an amplifier that amplifies the output (Acc-AC-x) of the first acceleration detection unit 11 and the output (Acc-DC-x) of the second acceleration detection unit 12.

In general, the output sensitivity and dynamic range of the acceleration sensor 10 differ depending on the detection method. For example, as shown in FIG. 10, the piezoelectric acceleration sensor 10 has a non-piezoelectric (piezoresistive, electrostatic) acceleration sensor. The output sensitivity is higher than 10, and the dynamic range is wide (large). In the present embodiment, the first acceleration detector 11 corresponds to the piezoelectric acceleration sensor 10, and the second acceleration detector 12 corresponds to the piezoresistive acceleration sensor 10.

Therefore, the gain adjustment circuit 21 sets the outputs (first and second acceleration detection signals) of the

acceleration detection units

11 and 12 to A times and B so that the outputs of the

acceleration detection units

11 and 12 are at the same level. Amplify twice. The amplification factors A and B are positive numbers and satisfy the relationship of A <B. The values of the amplification factors A and B are not particularly limited, and may be set as coefficients that also serve as temperature compensation of the

acceleration detection units

11 and 12 depending on the use environment (use temperature) of the acceleration sensor 10.

FIG. 11 is an example of output characteristics of the first acceleration detection signal and the second acceleration detection signal, and shows a comparison between the output characteristics before gain adjustment and the output characteristics after gain adjustment. In the figure, the horizontal axis represents the frequency of acceleration acting on the acceleration sensor 10, and the vertical axis represents output (sensitivity) (the same applies to FIGS. 12 to 15).

As shown in FIG. 11, in the piezoelectric first acceleration detection signal (Acc-AC-x), the output sensitivity of the acceleration component in the low frequency region of 0.5 Hz or less is higher than the acceleration component in the higher frequency region. The output sensitivity is substantially 0 particularly in a stationary state (motion acceleration is 0). On the other hand, the second acceleration detection signal (Acc-DC-x) of the piezoresistive method has a constant output sensitivity in the entire frequency range, so that the acceleration component in a stationary state (that is, gravitational acceleration) is also output at a constant level. It can be detected with sensitivity. Therefore, the gain adjustment circuit 21 amplifies the first acceleration detection signal and the second acceleration detection signal at a predetermined magnification so as to have the same output level, thereby calculating the gravitational acceleration in the difference calculation circuit described later. It becomes possible to do.

The sign inverting circuit 22 and the adder circuit 23 are configured to detect acceleration in each axial direction based on a difference signal between the first acceleration detection signal (Acc-AC-x) and the second acceleration detection signal (Acc-DC-x). The difference calculation circuit which calculates a static acceleration component (DC component) from is comprised.

The sign inverting circuit 22 has an inverting amplifier (amplification factor: -1) for inverting the sign of the first acceleration detection signal (Acc-AC-x) after gain adjustment. FIG. 12 shows an example of output characteristics of the first acceleration detection signal (Acc-AC-x) after sign inversion. Here, a case where the acceleration sensor 10 detects 1 G acceleration in the X′-axis direction is described as an example.

Note that the second acceleration detection signal (Acc-DC-x) is output to the subsequent addition circuit 23 without its sign being inverted. The sign inversion circuit 22 may be configured in common with the gain adjustment circuit 21 in the preceding stage.

The adder circuit 23 adds the first acceleration detection signal (Acc-AC-x) and the second acceleration detection signal (Acc-DC-x) output from the sign inversion circuit 22 to obtain a static acceleration component. Is output. FIG. 13 shows an example of output characteristics of the adder circuit 23. Since the first and second acceleration detection signals are adjusted to the same level in the gain adjustment circuit 21, the net static acceleration component (Gr-x) is calculated by obtaining these difference signals. Become. This static acceleration component typically corresponds to a gravitational acceleration component or an acceleration component including gravitational acceleration.

When the static acceleration component output from the adder circuit 23 is only gravitational acceleration, the output of a significant acceleration component appears theoretically only near 0 Hz as shown in FIG. However, in reality, the piezoelectric detection type first acceleration detection unit 11 has a low detection sensitivity in the vicinity of a low frequency, and the generation of other axis sensitivity causes an axis direction other than the target axis (here, the Y ′ axis direction and the Z axis direction). The dynamic acceleration component in the frequency domain indicated by hatching in FIG. 13 leaks to the output of the adder circuit 23 as an error component because the acceleration component in the “axis direction” inevitably overlaps. In view of this, the present embodiment includes a correction circuit 24 for canceling the error based on the output of the adder circuit 23.

The correction circuit 24 includes a triaxial composite value calculation unit 241 and a low frequency sensitivity correction unit 242. The correction circuit 24 calculates a correction coefficient β based on the output of the addition circuit 23 (difference signal between the first and second acceleration detection signals), and uses the correction coefficient β to generate the first acceleration detection signal (Acc− AC-x).

The three-axis composite value calculation unit 241 is provided in common for processing blocks that calculate all static acceleration components in the X′-axis, Y′-axis, and Z′-axis directions, and outputs (first and The correction coefficient β is calculated using the total value of the difference signal of the second acceleration detection signal.

Specifically, the triaxial composite value calculation unit 241 generates a composite value (√ ((Gr−x) ² + (Gr−) of static acceleration components (Gr−x, Gr−y, and Gr−z) in the triaxial direction. y) ² + (Gr−z) ² )) is calculated, and the amount of the combined value exceeding 1 G is regarded as a low-frequency sensitivity error (a region indicated by hatching in FIG. 13), and the reciprocal of the combined value is obtained. The corresponding correction coefficient β is calculated.
β = 1 / (√ ((Gr-x) ² + (Gr-y) ² + (Gr-z) ² ))

Note that the values of the static acceleration components (Gr-x, Gr-y, Gr-z) in each of the three axial directions vary depending on the attitude of the acceleration sensor 10 and are changed every moment according to the attitude change of the acceleration sensor 10. Change. For example, when the Z′-axis direction of the acceleration sensor 10 matches the gravitational direction (Z-axis direction), the static acceleration components (Gr-x, Gr-y) in the X′-axis direction and the Y′-axis direction The static acceleration component (Gr-z) in the Z′-axis direction shows the largest value. Thus, the gravitational direction of the acceleration sensor 10 at that time can be determined from the values of the static acceleration components (Gr-x, Gr-y, Gr-z) in the three axial directions.

The low-frequency sensitivity correction unit 242 includes a multiplier that multiplies the first acceleration detection signal (Acc-AC-x) whose sign is inverted by the correction coefficient β. As a result, the first acceleration detection signal is input to the adder circuit 23 in a state where the low-frequency sensitivity error is attenuated, so that an acceleration signal having a frequency characteristic as shown in FIG. Thus, as a result of outputting only the gravitational acceleration corresponding to the gravitational acceleration, the calculation accuracy of the gravitational acceleration component is improved.

In the present embodiment, the correction circuit 24 is configured to execute a process of multiplying the first acceleration detection signal by the correction coefficient β when calculating the static acceleration component. A process of multiplying the detection signal (Acc-DC-x) by the correction coefficient β may be executed, or the acceleration detection signal to be corrected is the first acceleration detection signal according to the magnitude of the acceleration change. And the second acceleration detection signal may be switched.

The correction circuit 24 corrects the first acceleration detection signal using the correction coefficient β when the acceleration change of one of the first acceleration detection signal and the second acceleration detection signal is greater than or equal to a predetermined value. Composed. The greater the change in acceleration (the higher the applied frequency), the higher the rate at which the error component leaks into the first acceleration detection signal, so that the error component can be efficiently reduced. This configuration is particularly effective when the motion acceleration is relatively large.

On the other hand, the correction circuit 24 corrects the second acceleration detection signal using the correction coefficient β when the change in acceleration of one of the first acceleration detection signal and the second acceleration detection signal is equal to or less than a predetermined value. Configured as follows. The smaller the acceleration change (the lower the applied frequency), the higher the rate at which the error component leaks into the second acceleration detection signal, so that the error component can be efficiently reduced. This configuration is particularly effective when the motion acceleration is relatively small.

The static acceleration component in each axis direction is calculated as described above. The dynamic acceleration components (Acc-x, Acc-y, Acc-z) in each axis direction are calculated as shown in FIG. In addition, the first acceleration detection signal (Acc-AC-x, Acc-AC-y, Acc-AC-z) whose gain is adjusted in the gain adjustment circuit 21 is referred to.

Here, the first acceleration detection signal may be used as it is for the calculation of the dynamic acceleration component, but a part of the dynamic acceleration component may leak into the static acceleration component as described above. The acceleration component is reduced, making it difficult to detect with high accuracy. Therefore, by correcting the first acceleration detection signal using the correction coefficient β calculated by the correction circuit 24, it is possible to improve the detection accuracy of the dynamic acceleration component.

More specifically, as shown in FIG. 8, the correction circuit 24 (low frequency sensitivity correction unit 242) uses the reciprocal (1 / β) of the correction coefficient β acquired by the triaxial composite value calculation unit 241 as the first acceleration. A multiplier for multiplying the signals (Acc-AC-x, Acc-AC-y, Acc-AC-z) is included. As a result, the low-frequency sensitivity component of the first acceleration signal is compensated, so that the calculation accuracy of the dynamic acceleration components (Acc-x, Acc-y, Acc-z) is improved. FIG. 15 schematically shows the output characteristics of the dynamic acceleration component.

The dynamic acceleration component and static acceleration component correction processing by the low-frequency sensitivity correction unit 242 is typically performed when the composite value calculated by the triaxial composite value calculation unit 241 is other than 1G (G: gravitational acceleration). It is considered effective. In addition, as a case where the said synthetic | combination value becomes less than 1G, when the acceleration sensor 10 is falling freely, etc. are mentioned, for example.

<Description of operation>
Next, processing of the control unit 61 of the camera gimbal 50 will be described. FIG. 16 is a flowchart showing processing of the control unit 61 of the camera gimbal 50 according to the first embodiment.

When the camera gimbal 50 is activated by turning on the power or the like, the control unit 61 causes the static acceleration components (Gr-x, Gr-y, Gr-z) output from the sensor unit 40 provided on the base 56 to The information on the acceleration components (Acc-x, Acc-y, Acc-z) and the angular velocity components (ω _x , ω _y , ω _z ) is acquired at a predetermined clock cycle (step 101).

Next, the control unit 61 includes a static acceleration component (Gr-x, Gr-y, Gr-z), a dynamic acceleration component (Acc-x, Acc-y, Acc-z), and an angular velocity component (ω _x , Based on nine elements of ω _y , ω _z ) and correction information for correcting the static acceleration component, corrected static acceleration components (Gr-x ′, Gr-y ′, Gr-z ′) ) Is calculated (step 102).

In this case, for example, the control unit 61 includes a matrix M (correction information) of 9 rows and 3 columns and nine elements (Gr-x, Gr-y, Gr-z, Acc-x, Acc-y, Acc-z). , ω _x, ω _y, by the transposed matrix X ^T vector omega _z), performs matrix calculation of Y ^T ⁼ MX T, corrected static acceleration component (Gr-x ', Gr- y', Gr-z ′) transpose matrix Y ^T is obtained.

Alternatively, the control unit 61 includes a matrix N (correction information), the transposed matrix X ^T, by the transposed matrix Z ^T of (before correction) static acceleration component (Gr-x, Gr-y , Gr-z) , Y ^T = NX ^T + Z ^T is executed to obtain a transposed matrix Y ^T of the corrected static acceleration components (Gr−x ′, Gr−y ′, Gr−z ′).

In the present embodiment, the matrix M and the matrix N are values prepared in advance and are stored in the storage unit 62. In this embodiment, the matrix M and the matrix N include static acceleration components (Gr-x, Gr-y, Gr-z), dynamic acceleration components (Acc-x, Acc-y, Acc-z) and This is correction information for correcting with angular velocity components (ω _x , ω _y , ω _z ). In this embodiment, the static acceleration component is corrected by both the dynamic acceleration component and the angular velocity component. However, the static acceleration component may be corrected by one of the dynamic acceleration component and the angular velocity component.

When the transposed matrix Y ^T is obtained, the control unit 61 obtains corrected static acceleration components (Gr-x ′, Gr-y ′, Gr-z ′) based on the transposed matrix Y ^T.

Note that the nine elements (Gr-x, Gr-y, Gr-z, Acc-) used to determine the corrected static acceleration components (Gr-x ', Gr-y', Gr-z ') x, Acc-y, Acc-z, ω _x , ω _y , ω _z ) may be a set of nine elements at the current time, or a plurality of sets from a predetermined time before the current time to the current time 9 elements may be used.

Once the corrected static acceleration component is calculated, the control unit 61 then determines the local coordinates based on the corrected static acceleration components (Gr-x ′, Gr-y ′, Gr-z ′). The direction of gravity in the system is determined (step 103). In this case, typically, the control unit 61 combines the corrected static acceleration components (√ ((Gr−x ′) ² + (Gr−y ′) ² + (Gr−z ′) ² ). ) Is determined to be the direction of gravity in the local coordinate system.

In the description of the present embodiment, a case where the gravity direction is determined based on the corrected static acceleration components (Gr-x ′, Gr-y ′, Gr-z ′) will be described. The determination may be made based on uncorrected static acceleration components (Gr-x, Gr-y, Gr-z) (the same applies to each embodiment described later). In this case, the control unit 61 determines that the direction in which the vector of the combined value of the static acceleration component (√ ((Gr−x) ² + (Gr−y) ² + (Gr−z) ² )) faces is the local coordinate system. Is determined to be in the direction of gravity.

Next, the control unit 61 calculates the rotation angle (θ _x , θ _y , θ _z ) in the local coordinate system based on the output (ω _x , ω _y , ω _z ) from the angular velocity sensor 30 (step 104). ).

Next, the control unit 61 determines the current posture of the pedestal 56 in the global coordinate system based on the information on the direction of gravity in the local coordinate system and the information on the rotation angle in the local coordinate system (step 105).

Next, the control unit 61 calculates a difference amount between the current posture of the pedestal 56 in the global coordinate system and the previous posture of the pedestal 56 in the global coordinate system (step 106). That is, the control unit 61 calculates a difference amount necessary for maintaining the posture of the pedestal 56.

Next, the control unit 61 rotates the pedestal 56 about three axes (X ′ axis, Y ′ axis, Z ′ axis) so as to cancel out the difference amount (step 107). At this time, the control unit 61 issues a command to the first motor 63a as necessary to rotate the first rotating member 53 about the z axis with respect to the shaft unit 52. Similarly, the control unit 61 issues a command to the second motor 63b as necessary to rotate the second rotating member 54 around the y-axis with respect to the first rotating member 53, so that the third motor A command is issued to 63c, and the pedestal 56 is rotated around the x-axis with respect to the pedestal holding member 55. In this way, the initial posture is maintained by the rotation of the pedestal 56.

<Action etc.>
As described above, in the present embodiment, the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the pedestal 56 (camera) and the dynamic acceleration component acting on the pedestal 56 (camera). The static acceleration component is calculated from the two signals, ie, the second acceleration detection signal obtained by detecting the static acceleration component.

Therefore, a static acceleration component that can be regarded as a gravitational acceleration component can be accurately calculated. Therefore, in the present embodiment, the control unit 61 can accurately determine the direction of gravity of the pedestal 56 (camera) in the local coordinate system, and thus accurately determine the attitude of the pedestal 56 (camera) in the global coordinate system. be able to. Therefore, the control unit 61 can accurately control the attitude of the base 56 (camera) in the global coordinate system.

Here, a case where a general acceleration sensor is used will be described as a comparison. A general acceleration sensor can detect a combined acceleration of a dynamic acceleration component (motion acceleration component) and a static acceleration component (gravity acceleration component), but cannot calculate a static acceleration component from the combined acceleration. Although it is conceivable to calculate the static acceleration component from the combined acceleration using a low-pass filter or the like, the accuracy is insufficient in calculating the static acceleration component.

Therefore, in a general acceleration sensor, for example, when the pedestal 56 (camera) has moved greatly, the acceleration that is the sum of the dynamic acceleration component (motion acceleration component) and the static acceleration component (gravity acceleration component). May be misrecognized as the direction of gravity. In this case, there is a problem that an image picked up by the camera is blurred or the subject is out of the angle of view.

On the other hand, in the present embodiment, as described above, the static acceleration component (gravity acceleration component) can be accurately calculated. Therefore, even when the pedestal 56 (camera) has moved greatly, the gravitational direction in the local coordinate system can be accurately determined based on the calculated static acceleration component. Therefore, even in such a case, the control unit 61 can accurately determine the attitude of the pedestal 56 (camera) in the global coordinate system, and can accurately control the attitude of the pedestal 56 (camera). As a result, it is possible to prevent the image from blurring and the subject from deviating from the angle of view.

In the present embodiment, the static acceleration component is corrected based on correction information for correcting the static acceleration component by the dynamic acceleration component and the angular velocity component. Since the gravitational direction is determined by the corrected static acceleration components (Gr-x ', Gr-y', Gr-z '), the accuracy of the determination of the gravitational direction can be further improved. The attitude of the camera 56 (camera) can be controlled more accurately.

<< Second Embodiment >>
Next, a second embodiment of the present technology will be described. In the description after the second embodiment, portions having the same configuration and function as those of the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted or simplified.

FIG. 17 is a flowchart showing processing of the control unit 61 of the camera gimbal 50 according to the second embodiment.

When the camera gimbal 50 is activated by turning on the power or the like, the control unit 61 first executes the stationary calibration mode (see step 201 to step 206). In the stationary calibration mode, the user places the camera gimbal 50 in a fixed position with the camera gimbal 50 in a basic posture and keeps the camera gimbal 50 stationary.

In the stationary calibration mode, first, the control unit 61 acquires information on the static acceleration component, the dynamic acceleration component, and the angular velocity component output from the sensor unit 40 in a stationary state at a predetermined clock cycle (step S1). 201).

Next, the control unit 61 adjusts (generates) the gain value and the offset value of the dynamic acceleration component so that the values of the dynamic acceleration components (Acc-x, Acc-y, Acc-z) become zero. (Step 202).

Next, the control unit 61 adjusts (generates) the gain value and the offset value of the angular velocity component so that the values of the angular velocity components (ω _x , ω _y , ω _z ) become 0 (step 203).

Next, the controller 61 performs static acceleration components (Gr-x, Gr-y, Gr-z), dynamic acceleration components (Acc-x, Acc-y, Acc-z) and angular velocity for the test. Based on the nine elements of the components (ω _x , ω _y , ω _z ) and correction information for correcting the static acceleration components, the corrected static acceleration components (Gr-x ′, Gr for testing) -y ', Gr-z') is calculated (step 204).

In step 204, for example, the control unit 61 ^performs a matrix operation of Y T = MX ^T, to obtain a transposed matrix ^{Y T} of the corrected static acceleration component (test). Alternatively, the control unit 61 ^performs a matrix operation of ^{^{Y T = NX T + Z T}} , to obtain a transposed matrix ^{Y T} of the corrected static acceleration component (test). Then, the control unit 61, from the obtained transposed matrix Y ^T, obtaining corrected static acceleration component (test).

Here, the nine elements (Gr-x, Gr-y, Gr-z, Acc-x, Acc-y, Acc-z, ω) used to determine the corrected static acceleration component (for testing) _x , ω _y , ω _z ) may be a set of nine elements at the current time, or may be a plurality of sets of nine elements from a predetermined time before the current time to the current time.

Once the corrected static acceleration component (for testing) is calculated, the control unit 61 then calculates the combined value (√ ((Gr−x ′ ) ² + (Gr−y ′) ² + (Gr−z ′) ² )) is calculated, and the magnitude of the vector is determined (step 205).

Next, the control unit 61 adjusts (generates) the matrix M (or the matrix N), the gain value of the static acceleration component, and the offset value so that the magnitude of the resultant vector becomes 1G (step 206). ). In the present embodiment, the matrix M (or matrix N), the static acceleration component gain value, and the offset value are correction information for correcting the static acceleration component.

When the stationary calibration mode is completed, the control unit 61 next executes a posture control mode (see Step 207 to Step 213) for controlling the posture of the camera in the camera gimbal 50.

In the attitude control mode, the control unit 61 executes the same processing as Step 101 to Step 107 in FIG. 16 of the first embodiment. In the second embodiment, in step 208, the matrix M (or matrix N), gain value, and offset value (see step 206) adjusted in the stationary calibration mode correct the static acceleration component. Used as correction information.

In the second embodiment, in the stationary calibration mode, the matrix M (or matrix N), static so that the magnitude of the vector of the combined value of the corrected static acceleration component (for test) is 1G. The gain value and offset value of the acceleration component are adjusted. In the attitude control mode, the matrix M (or matrix N) adjusted in the stationary calibration mode, the static acceleration component gain value, and the offset value (that is, the correction information) are corrected statically. Since it is used for calculation of the acceleration component, the direction of gravity can be determined with higher accuracy.

«Third embodiment»
Next, a third embodiment of the present technology will be described. The third embodiment is different from the above embodiments in that the camera gimbal 50 is attached to an unmanned flying object such as a drone (the flying object may be a manned airplane, helicopter, etc.). ing.

In the third embodiment, instead of the gripping part 51 in the camera gimbal 50, a connecting part (not shown) connected to the drone is provided in the camera gimbal 50. In addition, the camera gimbal 50 is provided with a communication unit that performs communication with the drone.

FIG. 18 is a flowchart showing processing of the control unit 61 of the camera gimbal 50 according to the third embodiment.

When the drone and the camera gimbal 50 are activated by turning on the power and the like and the flight of the drone is started, the control unit 61 of the camera gimbal 50 executes the attitude control mode (see step 301 to step 307).

The processing (step 301 to step 307) in the attitude control mode in the third embodiment is the same as step 101 to step 107 in the first embodiment, and thus the description thereof is omitted.

In the third embodiment, the stationary calibration mode may be executed before the attitude control mode, as in the second embodiment. In this case, the processing from step 301 to step 307 in the third embodiment is the same as the processing from step 207 to step 213 in the second embodiment.

When the control unit 61 executes the attitude control mode, the control unit 61 determines whether a command for the calibration mode during flight is received from the drone (step 308).

When the in-flight calibration command is not received from the drone (NO in step 308), the control unit 61 returns to step 301 and executes the attitude control mode again. On the other hand, when a command for the calibration mode during flight is received from the drone (YES in step 308), the control unit 61 executes the calibration mode during flight (see steps 309 to 312).

Here, when the in-flight calibration mode is executed, the drone stops the rotation of all the propellers in the drone while in the air and puts the drone into a free fall state.

In the in-flight calibration mode, first, the control unit 61 acquires information on the static acceleration component, dynamic acceleration component, and angular velocity component output from the sensor unit 40 at a predetermined clock cycle (step 309).

Next, the controller 61 performs static acceleration components (Gr-x, Gr-y, Gr-z), dynamic acceleration components (Acc-x, Acc-y, Acc-z) and angular velocity for the test. Based on the nine elements of the components (ω _x , ω _y , ω _z ) and correction information for correcting the static acceleration components, the corrected static acceleration components (Gr-x ′, Gr for testing) -y ', Gr-z') is calculated (step 310).

In step 310, for example, the control unit 61 ^performs a matrix operation of Y T = MX ^T, to obtain a transposed matrix ^{Y T} of the corrected static acceleration component (test). Alternatively, the control unit 61 ^performs a matrix operation of ^{^{Y T = NX T + Z T}} , to obtain a transposed matrix ^{Y T} of the corrected static acceleration component (test). Then, the control unit 61, from the obtained transposed matrix Y ^T, obtaining corrected static acceleration component (test).

Here, the nine elements (Gr-x, Gr-y, Gr-z, Acc-x, Acc-y, Acc-z, ω) used to determine the corrected static acceleration component (for testing) _x , ω _y , ω _z ) may be a set of nine elements at the current time, or a plurality of elements from a predetermined time before the current time (after the free fall state) to the current time. There may be nine elements in the set.

Once the corrected static acceleration component (for testing) is calculated, the control unit 61 then calculates the combined value (√ ((Gr−x ′ ) ² + (Gr−y ′) ² + (Gr−z ′) ² )) is calculated, and the magnitude of the vector is determined (step 311).

Next, the control unit 61 adjusts (generates) the matrix M (or matrix N), the gain value of the static acceleration component, and the offset value so that the magnitude of the combined value vector becomes zero (step 312). ). That is, when the drone is in a free fall state, the acceleration sensor 10 is in a weightless state, and the magnitude of the vector of the combined value is 0. Therefore, calibration is performed to match this. In the present embodiment, the matrix M (or matrix N), the static acceleration component gain value, and the offset value are correction information for correcting the static acceleration component.

The drone starts the rotation of the propeller after a predetermined time (for example, about several seconds) after stopping the rotation of the propeller, and puts the drone into a flight state.

When the camera gimbal 50 executes the in-flight calibration mode, the camera gimbal 50 returns to step 301 again to execute the attitude control mode. Here, in the attitude control mode, when the corrected static acceleration component is calculated (see step 302), the correction information adjusted in the in-flight calibration mode is used.

As described above, in the third embodiment, in the in-flight calibration mode, the matrix M (or the matrix) is set so that the vector value of the combined value of the corrected static acceleration component (for test) becomes 0G. N) The gain value and offset value of the static acceleration component are adjusted. In the attitude control mode, the matrix M (or matrix N) adjusted in the in-flight calibration mode, the static acceleration component gain value, and the offset value (that is, the correction information) are corrected statically. Since it is used for calculation of the acceleration component, the direction of gravity can be determined with higher accuracy.

In particular, in the third embodiment, the calibration can be automatically performed by the camera gimbal 50 when the drone is flying (in the air).

In the description of the third embodiment, the case where the drone is in the free fall state and the acceleration sensor 10 is in the weightless state when the driving of the propeller is stopped has been described. On the other hand, when the shape of the drone is an airplane type (fixed wing type) or the like, even if the propeller is stopped, the wing lift is generated and the drone does not fall freely. 10 may detect a constant acceleration.

Therefore, in such a case, in step 312, the control unit 61 sets the matrix M (or matrix N), static so that the magnitude of the composite vector becomes a predetermined value (not 0). Adjust the gain and offset values of the acceleration component. As the predetermined value that is the basis of the calibration, an appropriate value measured by repeating a test in which the propeller is stopped and the airplane-type drone flies is used.

Note that if the drone's airframe is an airplane type, even if the propeller drive is stopped in the air for calibration, the flight state can be kept stable to some extent.

≪Various modifications≫
In the above description, the case where the sensor unit 40 is arranged on the camera gimbal 50 side has been described. On the other hand, the sensor unit 40 may be disposed on the camera side. In this case, the sensor unit 40 is configured such that the acceleration in the direction of the three axes (X ′ axis, Y ′ axis, Z ′ axis) in the camera and the angular velocity around the three axes (X ′ axis, Y ′ axis, Z ′ axis) in the camera. Is detected and output to the camera gimbal 50.

In the above description, the camera gimbal 50 has been described as an example of the holding device. On the other hand, the holding device is not limited to the camera gimbal 50. For example, the holding device may be a holding device that holds an inertial navigation device (holding target), or may be a holding device that holds a rocket engine.

The processing of the control unit 61 (or the processing of the controller 20 of the sensor unit 40) in the camera gimbal 50 described above may be executed by the camera (that is, the holding target) (in this case, the camera (holding target) Attitude control device). Alternatively, this processing may be executed by a server device on the network (in this case, the server device is an attitude control device).

This technique can also take the following composition.
(1) Detecting a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding object, and the dynamic acceleration component and static acceleration component acting on the holding device Based on the static acceleration component calculated based on the second acceleration detection signal obtained by determining the gravitational direction in the holding device, the posture of the holding device is determined based on the gravitational direction. An attitude control device comprising a control unit that controls the attitude of the holding object by controlling.
(2) The attitude control device according to (1) above,
The control unit corrects the static acceleration component based on correction information for correcting the static acceleration component, and determines the gravitational direction based on the corrected static acceleration component. apparatus.
(3) The attitude control device according to (2) above,
The control unit corrects the static acceleration component based on the correction information for correcting the static acceleration component by the dynamic acceleration component.
(4) The attitude control device according to (2) or (3) above,
The control unit corrects the static acceleration component based on the correction information for correcting the static acceleration component by an angular velocity component acting on the holding device.
(5) The attitude control device according to any one of (2) to (4) above,
The control unit generates the correction information in a state where the holding device is placed at a certain position.
(6) The attitude control device according to any one of (2) to (5) above,
The holding device is attached to the flying object,
The control unit generates the correction information in a state where the flying object is in the air.
(7) The attitude control device according to any one of (1) to (6) above,
The first acceleration detection signal having an AC waveform corresponding to the dynamic acceleration component and the AC component corresponding to the dynamic acceleration component have an output waveform superimposed on a DC component corresponding to the static acceleration component. An attitude control device further comprising an acceleration calculation unit that calculates the static acceleration component based on the second acceleration detection signal.
(8) The attitude control device according to (7) above,
The attitude control device includes an arithmetic circuit that calculates the static acceleration component based on a difference signal between the first acceleration detection signal and the second acceleration detection signal.
(9) The attitude control device according to (8) above,
The acceleration control unit further includes a gain adjustment circuit that adjusts a gain of each signal so that the first acceleration detection signal and the second acceleration detection signal have the same level.
(10) The attitude control device according to (9) above,
The acceleration calculation unit further includes a correction circuit that calculates a correction coefficient based on the difference signal and corrects one of the first acceleration detection signal and the second acceleration detection signal using the correction coefficient. Attitude control device.
(11) The posture control device according to any one of (1) to (10) above,
A movable part that can move by receiving acceleration acting on the holding device, a piezoelectric first acceleration detection part that is provided in the movable part and outputs the first acceleration detection signal, and provided in the movable part And a non-piezoelectric second acceleration detection unit that outputs the second acceleration detection signal.
(12) The attitude control device according to (11) above,
The second acceleration detection unit includes a piezoresistive acceleration detection element.
(13) The attitude control device according to (11) above,
The second acceleration detection unit includes a capacitance type acceleration detection element.
(14) The first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding object held by the holding device, and the dynamic acceleration component and the static acceleration component acting on the holding object. Based on the static acceleration component calculated based on the second acceleration detection signal obtained by detecting, the gravity direction in the holding object is determined, and the attitude of the holding device based on the gravity direction A posture control device comprising a control unit that controls the posture of the object to be held by controlling.
(15) Detecting a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding object, and the dynamic acceleration component and static acceleration component acting on the holding device A detection unit that outputs a second acceleration detection signal obtained by
Based on the static acceleration component calculated based on the first acceleration detection signal and the second acceleration detection signal, a gravity direction in the holding device is determined, and based on the gravity direction, the holding device And a control unit that controls the posture of the holding object by controlling the posture of the holding device.
(16) Detecting a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding object, and the dynamic acceleration component and static acceleration component acting on the holding device Determining the direction of gravity in the holding device based on the static acceleration component calculated based on the second acceleration detection signal obtained by
A posture control method for controlling the posture of the holding object by controlling the posture of the holding device based on the gravity direction.
(17) Detecting a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding device that holds a holding object, and the dynamic acceleration component and static acceleration component acting on the holding device. Determining a direction of gravity in the holding device based on the static acceleration component calculated based on the second acceleration detection signal obtained by
Controlling the posture of the holding device by controlling the posture of the holding device based on the direction of gravity.

DESCRIPTION OF SYMBOLS 10 ... Acceleration sensor 11 ... 1st acceleration detection part 12 ... 2nd acceleration detection part 20 ... Controller 30 ... Angular velocity sensor 31 ... Angular velocity detection part 40 ... Sensor unit 50 ... Camera gimbal 61 ... Control part

Claims

By detecting the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding device that holds the holding object, and the dynamic acceleration component and the static acceleration component acting on the holding device Determining a gravitational direction in the holding device based on the static acceleration component calculated based on the obtained second acceleration detection signal, and controlling the posture of the holding device based on the gravitational direction; A posture control device comprising a control unit for controlling the posture of the holding object.
The attitude control device according to claim 1,
The control unit corrects the static acceleration component based on correction information for correcting the static acceleration component, and determines the gravitational direction based on the corrected static acceleration component. apparatus.
The attitude control device according to claim 2,
The control unit corrects the static acceleration component based on the correction information for correcting the static acceleration component by the dynamic acceleration component.
The attitude control device according to claim 2,
The control unit corrects the static acceleration component based on the correction information for correcting the static acceleration component by an angular velocity component acting on the holding device.
The attitude control device according to claim 2,
The control unit generates the correction information in a state where the holding device is placed at a certain position.
The attitude control device according to claim 2,
The holding device is attached to the flying object,
The control unit generates the correction information in a state where the flying object is in the air.
The attitude control device according to claim 1,
The first acceleration detection signal having an AC waveform corresponding to the dynamic acceleration component and the AC component corresponding to the dynamic acceleration component have an output waveform superimposed on a DC component corresponding to the static acceleration component. An attitude control device further comprising an acceleration calculation unit that calculates the static acceleration component based on the second acceleration detection signal.
The attitude control device according to claim 7,
The attitude control device includes an arithmetic circuit that calculates the static acceleration component based on a difference signal between the first acceleration detection signal and the second acceleration detection signal.
The attitude control device according to claim 8,
The acceleration control unit further includes a gain adjustment circuit that adjusts a gain of each signal so that the first acceleration detection signal and the second acceleration detection signal have the same level.
The attitude control device according to claim 9,
The acceleration calculation unit further includes a correction circuit that calculates a correction coefficient based on the difference signal and corrects one of the first acceleration detection signal and the second acceleration detection signal using the correction coefficient. Attitude control device.
The attitude control device according to claim 1,
A movable part that can move by receiving acceleration acting on the holding device, a piezoelectric first acceleration detection part that is provided in the movable part and outputs the first acceleration detection signal, and provided in the movable part And a non-piezoelectric second acceleration detection unit that outputs the second acceleration detection signal.
The attitude control device according to claim 11,
The second acceleration detection unit includes a piezoresistive acceleration detection element.
The attitude control device according to claim 11,
The second acceleration detection unit includes a capacitance type acceleration detection element.
Detecting a first acceleration detection signal obtained by detecting a dynamic acceleration component acting on a holding object held by the holding device, and the dynamic acceleration component and static acceleration component acting on the holding object The gravity direction of the holding object is determined based on the static acceleration component calculated based on the second acceleration detection signal obtained by the step, and the posture of the holding device is controlled based on the gravity direction. Accordingly, a posture control device including a control unit that controls the posture of the holding target.
By detecting the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding device that holds the holding object, and the dynamic acceleration component and the static acceleration component acting on the holding device A detection unit for outputting a second acceleration detection signal obtained;
Based on the static acceleration component calculated based on the first acceleration detection signal and the second acceleration detection signal, a gravity direction in the holding device is determined, and based on the gravity direction, the holding device And a control unit that controls the posture of the holding object by controlling the posture of the holding device.
By detecting the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding device that holds the holding object, and the dynamic acceleration component and the static acceleration component acting on the holding device Based on the static acceleration component calculated based on the obtained second acceleration detection signal, the direction of gravity in the holding device is determined,
A posture control method for controlling the posture of the holding object by controlling the posture of the holding device based on the gravity direction.
By detecting the first acceleration detection signal obtained by detecting the dynamic acceleration component acting on the holding device that holds the holding object, and the dynamic acceleration component and the static acceleration component acting on the holding device Determining a direction of gravity in the holding device based on the static acceleration component calculated based on the second acceleration detection signal obtained;
Controlling the posture of the holding device by controlling the posture of the holding device based on the direction of gravity.